Escalator handrail stop device

Abstract

The handrail of an escalator is continuously monitored for movement by a sensor assembly. In the event that the handrail stops moving, the escalator steps are stopped so as to provide a safe environment for passengers on the escalator. The system can also be used with moving walkways equipped with moving handrails.

What is claimed is: 
     
       1. An escalator safety assembly for monitoring escalator handrail movement, said assembly comprising: (a) means for producing a pulsed signal in response to movement of the handrail, said pulsed signal having a pulse rate which is proportional to the speed of movement of the handrail, said means for producing a pulsed signal comprising a roller contacting the handrail for rotation responsive to movement of the handrail, said roller carrying a metal plate fastened to a side of the roller;   (b) a sensor for monitoring said pulse rate, said sensor being operably connected to a power source for the escalator, and said sensor being operable to initiate an interruption of power from said power source when said pulse rate lies outside of a predetermined range corresponding to a range of acceptable handrail velocities and said sensor comprising an induction proximity sensor disposed adjacent to said roller; and   (c) audible alarm means connected to said sensor and actuable by the latter when said pulse rate initially strays from said predetermined range and prior to interruption of power.   
     
     
       2. The escalator safety assembly of claim 1 wherein said roller and said proximity sensor are mounted on a common lever so as to maintain a common geometric relationship one to the other. 
     
     
       3. The escalator safety assembly of claim 2 further comprising spring means engaging said lever to bias said roller against the handrail. 
     
     
       4. An escalator safety assembly for monitoring escalator handrail movement, said assembly comprising: (a) roller means mounted adjacent to the handrail and in contact with a surface of the handrail whereby the roller means will rotate at speeds which are proportional to the speeds of movement of the handrail;   (b) at least one discrete metal plate mounted on a side of said roller means;   (c) an induction proximity sensor disposed adjacent to said roller means and operable to sense passage of said metal plate as said roller means rotates;   (d) electronic control means operably connected to said proximity sensor and to a power source for the escalator, said control means being operable to receive pulsed signals from said proximity sensor at pulse rates corresponding to the rotational speed of said roller means, and said control means being operable to interrupt power to said escalator power source when said pulse rates fall outside of a predetermined range of pulse rates which confirm normal handrail speeds; and   (e) a sensible alarm means connected to said control means and operable to produce a sensible indication of handrail movement speed abnormalities prior to interruption of escalator power.   
     
     
       5. The escalator safety assembly of claim 4 wherein said roller means and said proximity sensor are mounted on a common lever adjacent to the handrail to maintain a common geometric relationship one to the other. 
     
     
       6. The escalator safety assembly of claim 5 further comprising spring means acting on said lever to bias said roller means against said handrail.